Some photoelectric conversion devices include a light absorbing layer comprised of a chalcopyrite-based Group I-III-VI compound semiconductor such as CIGS. As an example, these photoelectric conversion devices include a first electrode layer to become a rear surface electrode provided on a substrate, and the light absorbing layer comprised of a Group I-III-VI compound semiconductor and provided on the first electrode layer. Further, a transparent second electrode layer comprised of ZnO and the like is formed over the light absorbing layer while a buffer layer comprised of ZiS, CdS and the like is placed between the light absorbing layer and the second electrode layer.
As one of ways to enhance the photoelectric conversion efficiency of these photoelectric conversion devices, the size of crystal grains of the semiconductor contained in the light absorbing layer is increased. Japanese Patent Application Laid-Open No. 2000-156517 describes a technique of forming a light absorbing layer with large crystal grains.
However, if the light absorbing layer contains large crystal grains, contact force of the light absorbing layer to the electrode layer is reduced to make the light absorbing layer peel off the electrode layer easily. There arises a fear that this peel-off becomes a remarkable matter if the light absorbing layer is processed at a higher temperature in order to increase the size of the crystal grains in the light absorbing layer.
It is an object of the present invention to provide a photoelectric conversion device with high photoelectric conversion efficiency that increases reliability by increasing contact force between a light absorbing layer and an electrode layer.